To assess the clinical effectiveness of the locally delivered licorice extract as an adjunctive therapy to mechanical debridement in stage II periodontitis patients. To assess the impact of the locally delivered licorice extract as an adjunctive therapy to mechanical debridement on the level of interleukin-6 in the GCF in stage II periodontitis patients .

Periodontitis is a chronic multifactorial inflammatory disease associated with dysbiotic plaque biofilms and characterized by progressive destruction of the tooth-supporting apparatus. Its primary features include the loss of periodontal tissue support, manifested through gingival bleeding, presence of periodontal pocketing, clinical attachment loss and radiographically assessed alveolar bone loss (1).

Treatment of periodontal disease consists of plaque and calculus removal by scaling and root planing and good oral hygiene. Due to the bacterial etiology and inflammatory pathogenesis of periodontitis, the additional use of local or systemic antimicrobial agents and/or host response modulating agents has been proposed (2).

Locally applied therapy has received considerable attention due to the presence of a site-specific pattern of destruction in periodontal infections. It also provides effective local drug concentrations in the periodontal pocket and avoids potential side effects of systemic antimicrobial agents (2).

Conventional synthetic agents have some potential limitations like extrinsic teeth stains, altered taste sensation, and development of bacterial resistance that hinder its long-term usage (3). Herbal extracts are gaining attention since they contain phytochemicals which are naturally occurring ingredients that can achieve the desired antimicrobial and anti-inflammatory effects (4).

An example of such herb, with significant therapeutic value is "licorice (Glycyrrhiza glabra)". Licorice, is inherent to Mediterranean regions and few parts of Asia. The main active constituent of licorice is Glycyrrhetinic acid (GA), which is obtained from the extract of licorice root. Glycyrrhiza glabra shows anti-inflammatory effects due to the similarity in its chemical structure with glucocorticoids by initiation of glucocorticoid receptor signaling and also by inhibiting the classical complement pathway (5).

Licorice flavonoid components include chalcones, flavones, and isoflavones, which show antimicrobial (6), antiviral (7), anti-inflammatory (8), antidiabetic, antitumor, immunoregulatory (9), hepatoprotective (10) and neuroprotective activities (11).

The advantageous properties of licorice can be ascribed to several mechanisms. In vitro studies have established that licorice prevents cyclooxygenase activity and prostaglandin synthesis as well as indirect inhibition of platelet aggregation and all components in the inflammatory cascade (8). Licorice components possess important antioxidant properties. At the area of inflammation, licorice prevents the neutrophils from producing reactive oxygen species (12). Bioactive phytoconstituents of G. glabra inhibit the growth of periodontopathogens and reduce the inflammatory markers at the site of infection (13). It also ceases osteoclastic activity that contributes to alveolar bone destruction in periodontitis and promote the synthesis of osteoblasts for new bone formation (13).

Inclusion Criteria:

• Patients with Stage II Periodontitis (mainly horizontal bone loss with maximum probing depth ≤ 5 mm and with 3-4 mm clinical attachment loss).
• Age range (30 - 50) years.
• Good compliance with the plaque control instructions following initial therapy.
• Availability for follow up and maintenance program.

Exclusion Criteria:

• Smoking.
• Systemic diseases which could influence the outcome of the therapy (According to Cornell Medical Index-Health Questionnaire).
• Pregnant and lactating females.
• Vulnerable groups of patients' e.g (prisoners, disabled patients and decisionally impaired individuals).